The purpose of treating a histological sample, for example one taken from a patient, is to bring that sample into a state that permits sectioning into thin layers using a microtome. This treatment takes place in multiple processing stations. Sectionability can be enabled, for example, by the fact that in multiple successive processing steps, a mechanically stabilizing medium is introduced (infiltrated) into the tissue. Alternatively, the tissue can also be frozen.
A plurality of processing stations for processing histological samples are already known from the existing art. For example, processing stations in the form of trimming stations, fixing stations, dehydration stations, clearing stations, infiltration stations, embedding stations, or microtomes (sectioning stations) are known in a wide variety of embodiments. Dehydration, clearing, and infiltration can occur in different treatment stations of a single device, which is referred to hereinafter as a “processor.”
In a trimming station, the tissue (removed, for example, from the patient) is cut into individual samples. The samples are usually placed into cassettes and transported to a fixing station. Fixing of the samples is necessary because the supply of oxygen to the cells is suppressed after removal of the tissue from the patient, which results in cell death. Firstly a swelling of the cells can be observed; protein denaturing also occurs, and autolysis with subsequent bacterial digestion. In order to counteract this damage, the samples that have been removed are fixed in the fixing station with a fixative, for example formalin.
After treatment in the fixing station, dehydration of the samples occurs in a dehydration station. Dehydration of the samples is necessary in order to enable the subsequent process of infiltration and embedding.
Because the fixative (in particular formalin) is usually an aqueous medium, whereas the infiltration or embedding medium to be used (in particular paraffin) is usually a medium not miscible with water, the samples must be dehydrated before further treatment of the samples in the dehydration station. Dehydration of the samples is accomplished with the aid of a dehydration agent, for example ethanol.
Before the samples are transferred to the infiltration station, they are also cleared. Clearing is necessary because the alcohol in the tissue of the sample is not miscible with paraffin. The alcohol must therefore be removed from the tissue before infiltration, and replaced with a reagent miscible with paraffin, for example xylene.
After treatment of the sample in the clearing station, it is brought to an infiltration station. In the infiltration station an infiltration agent, which usually corresponds to the embedding agent used later, is introduced into cavities of the sample until it is saturated. Introduction of the infiltration agent allows the samples to be mechanically stabilized.
Following treatment of the sample in the infiltration station, it is processed in the embedding station. In the embedding station the histological sample is embedded into an embedding agent such as paraffin or wax. In practice, the term “embedding” is used in two ways. On the one hand it is a synonym for “infiltration,” which occurs in the aforementioned infiltration station; on the other hand, it has the same meaning as “embedding” or “block embedding,” which occurs in the embedding station.
For embedding, the samples are placed into molds and the mold is filled with the embedding agent. The histological sample is then cooled so that the embedding agent can harden. To cool the histological samples they are, for example, placed onto a cooling plate of the embedding station. The result is to create an embedded block in which the sample is immobilized in stationary fashion. After hardening of the embedding agent, the sample can be sectioned with the microtome into individual thin sample sections, which in a subsequent step can be stained and investigated with a microscope.
To ensure that the sectioning operation with the microtome can be carried out precisely, it is necessary for the embedded block to remain in a hard state. In practice, a laboratory worker transports the cassettes individually from the embedding station to the microtome. Alternatively, it is known that the laboratory worker does not transport the cassettes individually, but instead places them from the cooling plate of the embedding station into a transport basket. The transport basket is then transported to a microtome, with which the samples present in the transport basket are processed.
In embodiments known from the existing art, the fixed sample is removed from the fixing container by the user and put into the processor. In the processor, dehydration, clearing, and infiltration of the sample occur in the corresponding aforementioned treatment stations of the processor. The infiltrated sample is then delivered to an embedding station arranged physically separately from the processor.
The known embodiment is disadvantageous in that the fixing container must be manually opened in the laboratory in order to remove the samples. In addition, the user must manually take the samples out of the fixing container and introduce them into the processor. The result is that the user must perform a number of time-consuming working steps.
The object of the invention is therefore to make available a processor that decreases the number of time-consuming working steps carried out by the user of the processor.